The idea of using abrasive wheels for sharpening by means of grinding of helix tools (such as end mill cutters and the like) is not new. Perforce, very hard materials are used to constitute the abrasive component of such wheels including, for example, dust, chips or other pulverizations of natural and synthetic diamond forms, crushed silicon carbide (i.e., "Carborundum") and so forth.
The problem and significant operational draw-back in conventional practices and operations for helix tool sharpening by abrasive wheel grinding is that generally at least a two-step or -stage operation involving separate grinding set-ups and manipulations is required for completion of the procedure. By the usual means (as is hereinafter more thoroughly described), the peripheral land portion on the teeth of the tool being sharpened is sequentially removed from the "blank" or "stock" form being in process by generally at least two independent grindings done most commonly in a "back off" (sic) style of material removal with respect to the intended cutting edge(s) of the tool teeth. In this way, there is provided to the peripheral land of the end mill or the like being sharpened the necessary primary relief (and width of the primary relief land portion) and secondary clearance which must be achieved for satisfactory finished tool provision.
Helix tools sharpened without secondary clearance characteristics are generally not as desirable or effective as those having such features. Without any (or insufficient) secondary clearance, chip removal and heat-dissipating characteristics of the cutting tool are usually less than desired and, in many instances, due to having to employ excessive primary relief angles, there is an increased likelihood of encountering "chatter" in use of the tool on account of the insufficiently strong cutting edges resulting from too large primary relief angle constructions gotten into when no secondary clearances are involved.
As is evident, the two-stage grinding operation is less than ultimately efficient and requires considerable time and labor for, firstly, setting the work up for the primary relief making then, secondly and redundantly, re-setting the work up for the secondary clearance and associated primary relief width implementations and provisions. Needless to mention, it would be desirable to have economies capable of realization in the relatively cumbersome conventional practice of helix tool sharpening using abrasive wheels for the purpose while, at the same time, enabling the manufacture by a reliable and readily reproducible simplified process of at least equivalent if not superior quality sharpened products.
Representative prior art in the area of the present invention includes U.S. Pat. Nos.: (i) 2,396,505 (to C. Gumper); (ii) 3,049,843 (to F. L. Christensen--I); and 3,162,187 (to the same F. L. Christensen--II). These involve merely grinding wheel arrangements for surface finishing of such soft materials as rubber (as in the Gumper Patent) and/or abrasively-fitted circular saw blades for cutting through, and not surface finishing, bodies of such materials as concrete, marble and other natural stones, ceramics and so forth (as in Christensen I and II).
However, there is complete lack and literally nothing in prior art concerned with, teaching or leading to, in connection with the concept of abrasive wheels for helix tool sharpening: the achievement and provision of an advantageous and beneficial simultaneously double-acting split abrasive wheel for efficiently, effectively and most expediently sharpening such tools in a single operation imparting primary relief angles as wanted and needed, secondary clearances of the most advantageous and desired sort and most appropriately wide primary relief land surfaces; which wheel in any embodied form thereof is readily made, easily and accurately used with minimized attention and care needed for its operation and capable of giving excellent result reproducability and consistency in and for the sharpening of pluralities of tools in process; all with excellent durability and unusual wearability in and of the wheel adapting it for considerably prolonged usages without much need for re-dressing or discard and additionally, in toto, with the generally attractive and advantageous features of the sort and creation indigenous in the present contribution to the art.